Over the past several years there has been an improved treatment of Pneumocystis carinii pneumonia. Intravenous pentamidine appears to be less toxic than intramuscular pentamidine; dapsone-trimethoprim is somewhat better tolerated than trimethoprim-sulfamethoxazale; aerosolized pentamidine is better tolerated than any other currently available therapy; trimetrexate has been shown to be efficacious in relatively ill patients. To date there have been six patients enrolled on the study of which three are receiving dapsone and two receiving pentamidine. One patient was withdrawn. Patient enrollment is still being pursued. The pharmacokinetics of aerosolized pentamidine will be determined by the CPRL. In addition, therapeutic drug monitoring of dapsone will be undertaken by the CPRL.